Spreading the love: are Australian Sea Lions roamers or stayers?
For the last 2 years Sea World Research & Rescue Foundation have funded a research project focused on the breeding habits of the Australian Sea Lion (Neophoca cinerea), one of the rarest Sea Lions in the world.
The researchers examined male, female and offspring genotypes and found they have the highest level of site fidelity in marine mammals. Across their range there was little or no swapping of females among breeding colonies and only few instances of males’ siring (fathering) offspring in more than one colony. Most males proved loyal to their own breeding ground even when colonies were separated by as little as 20km.
Australian Sea Lion males also exhibited relatively low levels of variation in the number of females with which they breed, there were no obvious dominant or alpha males that bred more than others and there were no strong seasonal differences. This is good news for sea lions as the risk of inbreeding, which is caused by a limited gene pool, would be greater if only a small number of males dominated mating. Crucially for conservation however, the extreme site fidelity means that each colony represents an essentially closed population and highlights the importance of careful population management, especially with respect to impacts such as local fisheries bycatch.
On top of being the major contributor to the Sea World Research & Rescue Foundation, Sea World also cares for sick and injured Australian Sea Lions and New Zealand Fur Seals that have beached on the coast of Queensland and northern NSW.
Listed as Endangered in 2008 (IUCN Red List) the Australian Sea Lion population is described as small, isolated and decreasing. Funding from the Research & Rescue Foundation has made possible this investigation into the site fidelity of the Australian Sea Lion population and this quantifiable research data will contribute to the field of knowledge about managing the breeding sites of this endangered species.
Project title: Assessing male influence on population structure in the Australian Sea Lion
Researchers: Associate Professor Adam Stow and Dr Heidi Ahonen.
Photo Credit: Andrew Lowther
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